The invention relates to a recording and/or reproducing apparatus for use with a magnetizable record carrier in the form of a tape, and more particularly to such an apparatus which comprises at least one rotatable magnetic head which scans the record carrier along information tracks, the head being mounted on a support which has a hub by means of which the support is force-coupled to a rotatable shaft (hereinafter referred to as a "rotating head recorder"). The hub comprises at least one axially projecting tubular portion which is coaxial with the shaft and on which is placed a releasable clamping device for engaging the tubular portion and clamping it on the shaft so as to provide the force coupling between the support and the shaft. Such apparatus is known, for example, from Austrian Patent Specification No. 345 577.
In that known apparatus the clamping device is constituted by an annular, split, clamping ring which surrounds the tubular portion substantially over its full circumference in order to deform and thus clamp the tubular portion on the shaft. When the tubular portion is clamped in position, the clamping ring should uniformly tighten and urge the tubular portion against the shaft over substantially its entire circumference. This arrangement requires comparatively large deformation forces. However, the application of such large deformation forces may lead to a deformation of the shaft, which deformation remains after tightening and thus results in an eccentric rotation of the support when the shaft is driven. Such an eccentricity of the support, which may for example carry two magnetic heads, will adversely affect the recording and/or reproduction of information on and/or from the record carrier. For more information regarding the requirements for a highly accurate and also a highly reproduceable mounting of rotating vicks recorder head drums, reference may be made to U.S. Pat. No. 4,321,639; and to U.S. patent application Ser. No. 180,779 filed Aug. 25, 1980, and Ser. No. 389,536 filed June 18, 1982 which is a continuation of Ser. No. 144,730 filed Apr. 28, 1980, assiged to the assignee of the instant application (herewith incorporated by reference).